1. Field
The present disclosure relates to a composite anode active material, an anode including the composite anode active material, a lithium battery including the anode, and a method of preparing the composite anode active material.
2. Description of the Related Art
Carbonaceous materials, such as graphite, are representative examples of anode active materials suitable for use in lithium batteries. Graphite has good capacity retention and high potential characteristics, and ensures a battery's high stability because there is no volumetric change during the intercalation or deintercalation of lithium. Graphite has a theoretical electrical capacity of about 372 mAh/g and a high irreversible capacity.
In addition, metals that can form alloys with lithium may be used as an anode active material for lithium batteries. Examples of metals that can form alloys with lithium include silicon (Si), tin (Sn), aluminum (Al), and the like. These metals that can form alloys with lithium have a very high electrical capacity. For example, these metals may have an electrical capacity 10 times higher than that of graphite. Such metals undergo volume expansion or shrinkage during charging/discharging, thereby causing the active material within the electrode to become electrically isolated. In addition, the decomposition reaction of electrolytes becomes severe due to an increase in the specific surface area of the active material.
Therefore, there is a demand for a composite anode active material having an electrical capacity as high as those metals alloyable with lithium and which is capable of absorbing stress resulting from the volumetric expansion of metal to prevent the deterioration of the composite anode active material.